Switch



S. R. DU BRIE Jan. 21, 1936.

SWITCH Filed Oct. 8, 1954 2 Sheets-Sheet 2 INVENTOR JAMA w. BY 4 JATTORNEY.

Patented 21,

amass swrron Stanley a. D1: Brie, Detroit. that. Application mm tarsal,Serial No. 741.413

. Claims. (or 200-83) The switch disclosed in this application is of thepressure type and is operated automatically for circuit breaking whenthe pressure within a line or vessel connected to the switch exceeds apredetermined limit and. operates automatically for circuit making whenthe pressure within that vessel drops below a predetermined limit, the

differential between those limits being called the operating range ordifferential of the switch.

The switch here shown is characterized by its being provided, inaddition to the usual means for bodily shitting the diil'erential orrange of opening and closing pressure limits, with a means forincreasing or decreasing that differential -or range, the last mentionedmeans being adjustable without reference to the first mentioned means.

The switch here shown is also characterized by its having an interlocktype interconnection between operating parts or bell cranks o!- theswitch, the interconnection being formed by a tooth on one bell crankriding in a slot in the other, the operation being such that the slottedbell crank normally causes movement of the toothed bell crank. Theinterconnection is characterized by the feature that it cannot possiblycause locking of the connection between the bell cranks, in any relativeposition of the parts.

The switch is further characterized by the provision of a snap actionspring connection between operating parts or the switch, which springfunctions to provide quick make-and-break; these same operating partsare provided with a means for insuring positive break in the event thespring becomes broken or injured, or fails to function properly, thepositive break means becoming operable at a pressure higher than thenormal or spring opening pressure of the switch, so as not to interferewith the normal spring break means of the switch.

The switch is further characterized by the fact that the snap actionspring is adjustably mounted so as to provide anadjustment forincreasing or decreasing the difierential or range between the pressurelimits, and it will be observed that the spring adjustment alsofunctions to adjust the opening limit of the positive break means.

' The switch is also characterized by its being provided with a contactset of novel construction, whose details will be more particularlydescribed at a later stage of this specification.

For an understanding of the switch disclosed herein, the followingspecification should be read in connection with the appended drawings.In these drawings,

showing an important switch.

Fig. 1 is an elevational view or the switch with the cover removed;

. Fig. 2 is a view of the contact set per se as it from the right ofFig. l;

Fig. 3 is a top plan section view of the switch 5 with parts removed forpurposes of clarity;

Fig. 4 is a detailed section view as if on the line 4-4 of Fig. 3; r

Fig. 5 is a view as it from the right of Fig. 1,

operating part or the Referring to the drawings, it will be observedthat the switch therein shown comprises a base plate In and a casing II.Under the base plate, which is circular in form, but which has anapertured radially extending part I! projecting therefrom, is-a circulardiaphragm ll of heavy rubber or the like, and immediately under this'diaphragm is a chambered diaphragm plate l5. The base plate, thediaphragm, and the diaphragm 5 plate are relatively secured in assemblyto provide' a pressure chamber by means of the series of bolts l6. Twoof the bolts are passed through the base plate and into bosses l8 oi?the casing walls lla to secure the casing to the base plate, and thus tosecure the casing and the pressure chamher in assembly.

Disposed within the pressure chamber and above the diaphragm is apressure plate (not shown) provided with an upwardly extending pin 20engaging the horizontal arm 2! of the pressure bell crank 22, the latterbeing pivoted at 23 to bosses 23a formed integral with the base plate90. The vertical arm M is hooked over and has its upper end connected tothe side wall of the casing by a coiled tension spring 25 and anadjusting bolt 25 threaded through a nut 21. The last mentioned partsprovide a well-known means for bodily shifting the differential or rangeof opening or closing pressure limits of the switch, and adjustment ofthese parts for shifting the range is accomplished by movement of thenut 21 on the bolt 26.

The operating mechanism of the switch, as a whole, is connected to thevertical arm 24 of the pressure bell crank 22 through the tooth and slotconnection provided by a tooth 28 received within a slot 29 in the lowersurface ofthe hooked upper end of the bell crank 22. The tooth 28 isintegral with and projects upwardly from the hub 30 of a bell crank 3|,and this hub is secured to a threaded bolt or pin 32 which forms a fixedpivot or journal for the hub, the pin being secured to the casing wallllb.

The tooth 28 forms one arm of the bell crank 2|. The other arm, which ismore properly the switching arm. comprises two parts 22-2l,-ad- Justablyinterconnected through the medium or the screw 25 threaded into the partII through an elongated slot 22 o! the part 24. this constructionproviding an adjustment means whereby the length oi. the arm 33-" may bevaried to increase or decrease the differential or operating range ofthe switch. s V

For facilitating the 'adJustment when the-screw 35 is loosened,there'areiormed on the hub 20 two integral tapped-hole lugs "a throughwhich is threaded an adjusting screw'llb. It will be observed that whenthescrew 22b is rotated in the tapped lugs 20a, alter the screw 2| isloosened slightly, the part it may move or be'moved with respect to thepart-I2, all subject to the control of the o tor.

On mmd oi arm llll is a pin 21, and a coiled tension spring 39. whichforms an over center spring for the quick make-and-break or snapmechanism, has one end hooked around the pin 31. The other end of thisspring is hooked around a pin 48 projecting i'rom the arm ll of a bellcrank 42, the latter being iournalled at its elbow on a fixed pivot 42in the form of a bolt threaded into the wall lib oi the casing i I. Thevertical arm ll of the bell crank l2 is the switch contact arm and hasat its lower end a hole through which passes a rod ll of insulatingmaterial such as fiber or the like, on the opposite ends 01 which aredisposed metallic sleeves 40 which form the movable contacts or thecontact mechanism, and which engage the stationary spring contacts 41mounted on the insulating block 42 disposed against the side wall Ho 01the casing ii. 7

'I'heblock It isheld in place by screws II which mount the contacts ll,these screws projecting through the casing wall to form externallyaccessible binding posts. whereby the load and line conductors may besecured in electrical and physical connection with the contacts 41, theconductor terminals and the binding screws being protected by a shield52 secured over them and to the side wall of the casing, over theapertured extending part i2 oi the base plate.

It will be observed that when the pressure bell crank 22 rocks clockwise(Fig. l) on an increase in pressure, the bell crank 2i will rockclockwise on its iixed pivot -32 until the arm 22- and coil spring 22-move over center with respect to the pin 40 and the fixed pivot 43 ofthe bell crank 42.

Such movemeht causes the bell crank 42 to move for quick break, from theposition shown, counterclockwise, on its fixed pivot l3 and move thecontact sleeves it out 01! contact maldng position and from thestationary-contacts l'l. Conversely, a decrease in pressure will causethe switch to close, if it had been opened, the over center arrangementproviding quick make movement for the parts.

The stationary contacts 41, of which there is a pair for each sleeve 46,or tour contacts in all, comprise copper spring members bent to'theformation shown in Fig. 1.

The contacts 41, at their bights, are slotted as I indicated at lid forthe purposes of maintaining proper alignment of the portions of thecontacts toact as a switch is opened on an increase in pressure. Therelative position of the parts "-58 issuch that they will not bemutually engaged until the bell crank 42 has moved sumciently to havethe sleeve 48 clear-the contact 41 a considerable distance.

In order. to provide a positive break means which is normallyinoperative but which can be relied upon to cause break in the event thespring 29 becomes broken or injured or otherwise fails to function, thepart 3| oi'the switching arm is provided with an extension which willengage the arm ll 0! the bell crank 42 on an instop for the switch partswhen the crease in pressure to a point beyond the normal switch andthepositive break pressure isa I constant.

It will also be observed that the interlock interconnection between thebellcranks 22 and ii, provided by the tooth 28 and the slot .28receiving it, is an eflicient, non-binding, and otherwise satisfactorytwo-way connection between these bell cranks, and is not ailected bycooking. of the bell cranks with respect to each other as might be thecase ii. a floating pivotwere relied upon as a connection between thebell cranks 22 and 2|. Further, the engagement of-a tooth side with aslot side prevents overtravel of the switch arm 22-34. J

It will also be observed that part 24 01! the switching arm is providedwith a lug 80 riding over the upper surface of the part 22, whichprevents pulling oi. the switching arm as a whole when the adjustingscrew is loosened; such buckling being due to the pull of spring. 29which tends to cause movement of the part 2| clockwise around the screw35. Buckling in the opposite direction is, or course, prevented bytheadlusting screw 38b.

Now having describedthe switch that is dis-' the scope of the monopolyclaimed herein.

What 'I claim is: I

1. A pressure switch means comprising an operating bell crank, meanstending to rotate the same in one direction on an increase in pressure,adjustable resilient means tending to rotate the same in the oppositedirection, the two means being in opposition, a contact making bellcrank, and a connector bell crank having one arm operatively connectedto an armor the operating bell crank through a positive connection andhaving another arm operatively connected to an arm of the contact makingbell crank through an adiustable resilient connection which provides anover center snap action for the contact carrying bell crank.

2. A pressure switchmean's comprising an operating bell crank, meanstending to rotate the same in one direction on an increase in pressure,adjustable resilient means tending to rotate the same in the oppositedirection, the two means being in opposition, a contact making bellcrank, and a connector bell crank having one arm operatively connectedto an arm of the operating 7 aocsnoc of the contact making bell crankthrough an adjustable resilient connection which provides an over centersnap action for the contact carrying beii crank, the adjustment for theresilient means of the operating crank providing means for bodilyshifting the difierentiai or pressure range of the switch withoutvarying that difierentiai.

3. A pressure switch means comprising an operating bell crank, meanstending to rotate the same in one direction on an increase in pressure,adjustable resilient means tending to rotate the same in the oppositedirection, the two means being in opposition, a contact making bellcrank, and a connector bell crank having one arm operatively connectedto an arm of the operating bell crank through a positive connection andhaving another arm operatively connected to an arm of the contact makingbell crank through an adjustable resilient connection which provides anover center snap action for the contact carrying bell crank, theadjustment for the resilient connection providing means ior varying thediflerential or pressure range of the switch without bodily shiftingthat difierential.

4. A pressure switch means comprising an operating bell crank, meanstending to rotate the same in one direction on an increase in pressure,adjustable resilient means tending to rotate the same in the oppositedirection, the two means being in opposition, a contact making belicrank, and a connector bell crank having one arm oper atively connectedto an arm of the operating bell crank through a positive connection andhaving another arm operatively connected to an arm of the contact makingbell crank through an ad justabie resiiient connection which provides anover center snap action for the contact carrying hell crank, theadjmtinent for the resilient means of the operating cralm providingmeans for hodiiy shifting the difierentiai or pressure range oi theswitch without varying that differential, the adjustment for theresiiient connection providing means for varying the difierentiai orpressure range of the switch without bodily shifting that difierentiai.I

5. A pressure switch means comprising an operating hell crank, meanstending to rotate the same in one direction on an increase in pressure,adjustable resilient means tending to rotate the same in the oppositedirection, the two means heing in opposition, to contact making heiicrank, and a connector bell crank having one arm operatively connectedto an arm of the operating bell crank through a positive connection andhaving another arm operativeiy connected to an arm of the contact makinghe'il crank through an adjustable resilient connection which provides anover center snap action for the contact carrying hell crank, theadjustment for the resilient means oi the operating crank providingmeans for co-diiy shifting the ciifierentiai or pressure range of theswitch without varying that differentiai, the adjustment for theresilient connection providing means for varying the difierentiai orpressure range of the switch without bodily shitting that differential,with the first mentioned one being accessible from outside the switchcasing and with the second mentioned one heing accessible only frominside the switch casns.

STAImY R. DU BRIE,

